High-speed slewing



Sept. 23, 1952 D. o. MCCOY 2,611,893

HIGH-SPEED SLEWING Filed March 30, 1951 k l RANGE msmr PHASE 7 BLOCK/Nfi m ostnulmn smrrzn osmuTaR m AY Bmamns Z I "g P501514: 23

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Y DAVID O. M Coy A T TORNE Patented Sept. 23, 1952 HIGH-SPEED SLEWING David 0.,M cCoy, Cedar Rapids, Iowa, assignor to Collins Radio Company, Cedar Rapids, Iowa, a

corporation of Iowa Application March 30, 1951, Serial No. 218,359

This invention relates in general to range sys: tem and in particular to a ranging system for radar. A I I In radar techniques it is desirable to determine two things-(1) the direction of a target and (2-) the distance to the target.

lhe direction of the :target is relatively easy to determine in that-the antenna may. be rotated to point directly toward the target and its angle noted. To determine the distance, however, either a triangulation problem must be solved or the time of travel of anecho from the target must be known. The triangulation method requires two transmitters located at different points and therefore generally the measurement of the time required for the echo to return is usedfor determining range. Since radiowaves travel approx imately at the speed of light the time delay before the echo-of transmitter pulse is received is equal to twice the time that it took the reflected energy to return from the target. Thus, if the time between transmission of the impulse and reception ofthe echo is known, the distance to thetarget may be obtained. For example, it is known that it takes approximately six microseconds for a radio wave to travel 1,000 yards. A frequency of 164 kilocycles per second has a cycle every six microseconds and thu might be used as a time reference base.

It is an objectof this invention, therefore, to provide a range system which will swiftly and accurately track a target andindicate its range.

Yet another object of this invention is to provide a ranging system which may be swiftly changed along its distance base to pick up. targets whicn are spaced great distances from each 7 other.

Yet another object of this invention is to provide an improved ranging system' for swiftly loeating atarget. j

A feature of this invention is found in'the provision for a detent mechanism connected between the coarse and fine range'indicators so thatthe apparatusmay be swiftly changed over the lim it's of the ranging system.

Further objects, features and advantages of" 7 Claims. (Cl. 34313) 164 kilocycles per second and supplies an output to phase shifter ll. Phase shifter I! produces four outputs spaced 90 degrees apart and furnishes them toa goniometer l2. The phase shifter I l produces one output which is in. phase with the mastercscillatorlll output, and second, third, and fourth outputs which are 90 1'80, and 270 degrees displaced from the oscillator output.

The goniometer !2 produces one output of the same frequency as the output of oscillator ID. The phase of the .goniometer output is determined by the position of the goni-ometers shaft l3. As the shaft I3 is rotated the phase of its output will vary. directly as the position of the shaft. The output of goniometer i2 is fed to a blocking oscillator I 4 which changes the shape of the sine wave input to pips which are evenly spaced with the time between them being equal to the period ofthe incoming signal.

A second blocking oscillator it receives an output from master oscillator to and changes the sine wave output to-a plurality of pips with one pip for each cycle of the sine wave. The output of blocking oscillator 96 is furnished to a ref-'- erence pulse selector H which is actuated bya reference pulse supplied to the terminal IB. The reference pulse supplied to the terminal Ill might correspond in time to the transmitter pulse which turns on the transmitter of the radar set. Each time a reference pulse is received at terminal l8 one pip is allowed to pass through selector H.

A delayed-pulse generator l9 receives an out-.- put from the pulse selector I! and produces an output at a time subsequent to the input. A multi-turn potentiometer 2| furnishes an electrical signal to the delayed-pulse generator I9 to vary the delay time of the delayed pulse generator l9. For example, with various inputs from potentiometer 21, various time delays are obtained inthe output of the generator iii The output of potentiometer 2| is controlledby its shaft posi' tion and the shaft 2-! may be rotatedby suitable drivin means.

A pedestal generator 23' receive the output of the generator [9 and produces a pedestal output each time an input is received. A mixer 24 receives an input from thewblocking oscillator l4 and the pedestal generator 23 and is biased to cutoff at all times except when a pedestal is supplied from the generator 23. During this time a pulse from the blocking oscillator l4 isallowed to pass through the mixer 26-. The pedestal from the generator is slightly longer than the distance between adjoinin pips so that each time a 56 pedestal'is furr'iished to mixer 24, at least one pip an indicator 26 and to a motor 21.

tent mechanism must have 10 positions.

will be passed. It is to be observed that if a pulse occurs shortly after the reception of the pedestal from the generator 23 that it is possible for two pulses to pas the mixer 24. The first pip passed is used as a range reference pulse andif two pulses are passed, only the first one controls.

-,The shaft l3 of goniometer I2 is connected to The motor 21 is alsoconnected to a gear reduction 28 which is in turn connected to a detent mechanism 29. The shaft output of the detent mechanism 29 is connected to handle 3| and the shaft 22. An indicator 33. indicates the angular position of the shaft 22.

The output of goniometer l2 determines the fine adjustment of the ranging system and the output of the potentiometer 2| determines the coarse adjustment. For example, if one rotation of the shaft i3 corresponds to a change in range of 1,000 yards, one turn of the potentiometer 2| might correspond to 10,000 yards, so that the shaft l3 turns 10 times each time the shaft 22 motor 21 will drive the goniometer l3 and potentiometer 2| until this range is reached, but the indicator 26will have to make 60 revolutions, While the pointer 34 is making six revolutions and the pointer 36 is making 0.6 of a revolution. Quite a period of time is requiredto turn indicator 26 sixty revolutions.

It is therefore desirable to provide. the detent mechanism 29 which will allow a rapid change "for a, large range gradient. Thus, the handle 3| is provided to turn the potentiometer 2| while maintaining the goniometer shaft l3 stationary.

The detent mechanism 29 is designed to always stop in positions which are synchronized with the goniometer shaft |3 so that no misalignment occurs when the handle 3| is turned.

jFor example, if it is desired to synchronize shafts 3 and22 at 1,000 yard position, the de- The shafts may be synchronized every 2,000 yards and this requires only positions of the detent mechanism 21. The calibration of indicators 26 and 33 must also be changed for the differen conditions.

As shown in Figure 2, the detent mechanism comprises aninput shaft 31 and an'output shaft 38. The input shaft 31 has mounted thereon a sleeve 39 which has aplate 4| connected to one end. The shaft 31 is received within the sleeve .39 and a spring 42 is mounted about the shaft 31 and sleeve 39'to engage the plate 4 A washer 43 is mounted on the shaft 31 and a holding means 44 is mounted on the shaft 31 adjacent the washer 43. The spring 42 is fitted down-over the sleeve 39 and the washer 43 is slipped down to engage the top of spring 42. 'The holding means 44 is then tightened to the shaft 31 to hold the spring 42 and washer 43 in place. Thus,

' the plate 4| and sleeve 39 are always urged away from the end of shaft 31. I

The shaft 38 has a plate 46 mounted to its free which they are farthest from the shaft 31. The

depressions 41 formed in the plate 43 will thus maintain a predetermined angular relationship between the shafts 31 and 38. If the shaft 31 is prevented from rotating and the shaft 38 is rotated the balls 48 will ride up over the crests 5| between depressions 41 of the plate 46 and will move to the bottom of the adjacent depressions.

As long as the shaft 31 is free to rotate the shafts 31 and 38 will move together for the reason that the spring 42 is strong enough to transreference pulse must be walked along intime" until it is superimposed on the leading edge of the echo. The range reference pulse may be moved or walked along by rotation of shafts l3 and 22.

, Suppose the target is located 64,500 yards from the transmitter. If shafts |3 and 22 start from 22,000 yards, a relatively long time will be required forthe motor 21 to move them out to 64,500 yards. If the operator turns the handle 3| four and two-tenths revolutions, the "range unit will be immediately set at 64,000 yards-and the motor 21 need only drive shafts l3 and 22 until 500 yards is read on goniometer IS.

The pointers 28, 34 and 36 alwaysindicate the range. For example, at a range of 64,500, pointer 26 will read 500 yards, pointer 34 will read 4,000 yards, and pointer 36 will read 60,000 yards It is to be understood that the operator controls motor 21 in both direction of rotation and speed in order to range automatically, For example, in tracking a moving target which has been previously located, the motor 21 will track rapidly enough to follow it. However, if it is desired to change from one target to another with a greatly varying range, the motor is too slow and the operator uses the handle 3|.

It is seen that this invention greatly speeds up range changes and aids in measuring the range of new targets rapidly and accurately so that they may be destroyed before reachinga critical location.

Although this invention has been described. with respect to a preferred embodiment thereof, it is not to be so limited as changes and modifica tions may be made therein which are within-the full intended scope of the invention as defined by the appended claims.

shaft that controls the fine adjustments of range,

a driving means connected to the goniometer shaft, a gear reduction connected to said driving 5 means, a detent mechanism connected to said gear reduction, the shaft of said multi-turn potentiometer connected to said detent mechanism, and a crank connected to said multi-turn potentiometer shaft.

control shaft of the multi-turn potentiometer, a crank connected to the control shaft of the 1 multi-turn potentiometer, and a driving means a connected to the goniometer shaft.

with a control shaft that controls the coarse adjustments of range, a goniometer with a control 1 shaft that controls the line adjustments of range,

a crank connected to the multi-turn potentiometer shaft to allow rapid manual range changes tobe made, a synchronizing detent connected to the multi-turn potentiometer shaft, a gear reduction connected to the opposite side of said detent, the opposite side of said gear reduction connected to said goniometer shaft, and a driv- :ing means connected to said goniometer shaft.

3. Means for quickly making large changes in range comprising, a multi-turn potentiometer with a control shaft that controls the coarse adjustments of range, a goniometer with a control shaft that controls the fine adjustments of range,

a crank connected to the shaft of the multi-turn potentiometer, a detent mechanism connected to i z the shaft of the multi-turn potentiometer, a gear reduction connected to the opposite side of said detent mechanism, the shaft of said goniometer connected to the opposite side of said gear reduction, and a driving means connected to the goniometer shaft for automatic ranging.

4. Means for quickly making largechanges in range comprising, a multi-turn potentiometer with a control shaft that controls the coarse adjustments of range, a goniometer with a control 3.

shaft that controls the fine adjustments of range,

6. Means for quickly making large changes in range comprising, a multi-turn potentiometer with a control shaft that controls the coarse adjustments of range, a goniometer with a control shaft that controls the fine adjustments of range,

a gear reduction connected to the goniometer shaft and having a reduction ratio equal to the range changing effect of the potentiometer shaft relative to the goniometer shaft, a detent mechanism connected to the opposite side of said gear reduction, the opposite side of said detent mechanism connected to the potentiometer shaft, a crank connected to the potentiometer shaft, and a driving means connected to the goniometer shaft for automatic ranging.

'7. Means for quickly making large changes in range comprising, a multi-turn potentiometer withpa control shaft that controls the coarse adjustments of range, a goniometer with a control shaft that controls the fine adjustments of range, a gear reduction with a reduction ratio equal to V the range effect of the potentiometer shaft to the goniometer shaft connected to said gonioma detent mechanism connected to a gear reduction, said gear reduction and said detent mechanism connected in series between the goniometer shaft and the multi-turn potentiometer shaft, driving means connected to said goniometer shaft, and a crank connected to said multi-turn potentiometer to allow rapid manual changes in range.

5. Means for quickly making large changes in range comprising, a multi-turn potentiometer eter shaft, a detent mechanism connected to said gear reduction, the opposite side of said detent mechanism connected to said potentiometer shaft, a driving means connected to said goniometer shaft, a crank connected to said potentiometer shaft, and said detent mechanism having a number of steps equal to the gear reduction ratio.

DAVID O. MCCOY;

, No references cited. 

